The purpose of this proposal is to evaluate serial changes in cardiac function following acute myocardial infarction in order to assess the prognostic implications of the functional deficit produced by acute infarction. Emphasis will be placed on the use of technitium albumin gated wall motion studies. Additional indicators of infarct size will include thallium-201 perfusion scanning and technetium-99 pyrophosphate infarct sizing. Initial data suggests that these two latter measurements have important prognostic implications in the long-term follow-up of patients following acute myocardial infarction. We have made recent progress in more quantitative aspects of thallium perfusion imaging and wall motion studies. Computer assisted techniques for quantitating these studies have helped greatly in objectively defining the results in a quantitative fashion. Related studies in the Animal Laboratory have utilized implanted tantalum screws for evaluating segmental and global function in the dog with an intact chest and pericardium. These studies do not require the injection of contrast material and, therefore, provide for an essentially noninvasive way of following myocardial infarction produced by occlusion of a coronary artery by inflation of a balloon tipped catheter.